In addition to the Drag and Drop method you can manually add links to the link group. As in the Drag and Drop method you will have to select the link group you are adding to.
To add a new link you can use either Edit|New Link in the Main Menu or the Right Click menu, and lastly you can select the New Link button. The Link Item Properties will open to the General Tab. By default the new link item will be given the next sequential default link name.
You can change the name if you wish.
If you are using
About the Link Item General Page
Name - This parameter allows you to enter the string that will represent the data available from this link tag. The name can be up to 31 characters in length and must be unique within any given link group.
Description - This parameter allows you to attach a comment to this tag. A string of up to 64 characters can be entered for the description. If you are using an OPC client that supports Data Access 2.0 Tag Properties, the description parameter will be accessible from the Item Description property of the tag.
Read- only client access - This selection allows you to specify whether this link is "Read only" or "Read/Write". By selecting Read Only, you can prevent client applications from changing the data contained in this tag. Otherwise, leaving this setting unchecked will allow client applications to change this link tag's value as needed. The "Client access"
selection also affects how this tag will appear in the browse space of an OPC client.
Many OPC client applications allow you to filter tags based on their attributes. Changing the access method of this tag may change how and when the tag will appear in the browse space of your OPC client.
Next you will select the Input tab. The Link Item Input allows you to define the source of data that will be transferred to one or more output items. This value will be read from your target OPC server at the rate specified in your Link Group settings.
In the Input tab of the Link Item Properties window you will establish the Machine name by selecting the Machine/PC where the server you want is. Once the machine/PC selected you will select the server from the Server Name drop down list. You can type the Item ID of the tag you want as the input or you can use the Browse button to open the browse window and select the tag you want.
In the Browse window find the tag you want as an input and double click on it. As seen below the proper Item ID will we written to the Item ID field and the Data type will be changed to match that of the tag that was selected.
About the Link Item Input Page
Machine Name - You may choose either your local machine or a machine located on your Ethernet network (if any are available). If the server is located on the same machine as the LinkMaster, you can leave the setting as "Local Machine"
Server Name - Allows you to choose the OPC server from which you want to get source data from. In this case the Input data will be coming from KepserverEx.
Access Path - This is required by some OPC servers to complete an item definition.
Refer to your OPC server's documentation to determine whether or not you need to specify an access path.
Item ID - The OPC server item used to reference the data. Refer to your OPC server's documentation to determine valid item names for the location in question. If the server supports tag browsing then you can select an item by using the browse feature.
Data Type - This is the requested data type that should be used when communicating between the OPC server and the OPC LinkMaster. This should be specified to agree with the size and type of the register or memory location that is being addressed. Supported data types are defined as follows:
Native Default as determined by the OPC server Boolean Single bit
Char Signed 8-bit value Byte Unsigned 8-bit value Short Signed 16-bit value Word Unsigned 16-bit value Long Signed 32-bit value DWord Unsigned 32-bit value
Real Single precision floating point value. (32-bits) Double Double precision floating point value (64-bits) String Zero terminated character array
All of these are available as Array types except for Boolean and String.
At this point you can click on the Output tab to define the link output.
Link outputs allow you to define one or more OPC items that will be written to, when the Input item changes. The link's Output dialog allows you to, browse and select an available local or remote machine, choose an OPC server on the selected machine, and then select any of the desired tag items located on that server, as outputs.
You are allowed to add as many outputs as needed in the link item output section. Enter the item you want in the Item ID and click the Add button (or double-click).
You may also remove any output item at any time by highlighting the item in the output display and clicking the Remove button.
Any changes that are made to existing outputs can only be updated by pressing the Update button.
About the Link Item Output Page
If you are using
Item ID - The OPC server item used to reference the data. Refer to your OPC server's documentation to determine valid item names for the location in question. If the server supports tag browsing then you can select an item by using the browse feature.
Data Type - This is the requested data type that should be used when communicating between the OPC server and the OPC LinkMaster. This should be specified to agree with the size and type of the register or memory location that is being addressed. Supported data types are defined as follows:
Native Default as determined by the OPC server Boolean Single bit
Char Signed 8-bit value Byte Unsigned 8-bit value Short Signed 16-bit value Word Unsigned 16-bit value Long Signed 32-bit value DWord Unsigned 32-bit value
Real Single precision floating point value. (32-bits) Double Double precision floating point value (64-bits) String Zero terminated character array
All of these are available as Array types except for Boolean and String.
LinkMaster supports Link Item scaling, which allows raw input data from your server to be scaled to a more appropriate range for your Link Output item or client application. There are two types of scaling: Linear and Square Root. If you need to scale your input data then you can select the Scaling tab at this time.
Selecting either Linear or Square Root scaling will enable scaling operations for the Link Item.
The raw data range allows you to specify the range of raw data from the server. The valid range is dependent upon the data type of the Link Item's raw value. If, for example, the raw value was set to Short, the valid range of the raw value would be -32768 to 32767. The raw high range must be greater than the raw low range.
Normally a scaled value is assumed to result in a floating-point value. LinkMaster does not make that assumption for you. The data type of the "Scaled Value" can be set to any valid OPC data type. This gives you the ability to scale from a raw data type, such as Short, to an engineering value with a data type of Long, if it is needed. The default scaled data type is "Double".
The scaled data range allows you to specify the range of the resulting scaled value. The valid range is dependent upon the data type of the scaled value. If, for example, the scaled data type is set to Long the valid range is -2147483648 to 2147483647. The scaled high range must be greater than the scaled low range.
In many cases the raw data from the device exceeds the range you have specified for the raw data.
When this occurs the scaled value is also forced outside of the range you have established. To prevent this, the High and Low clamps can be used to constrain the scaled value to the range specified.
LinkMaster also allows a unit’s string to be assigned to a scaled Link item. The unit’s string can be up to 32 characters long.
OPC clients that have already connected to this Link item tag will not be affected until they release and reacquire this tag.